A Brief History of Disposal Part 4. Treatment

Dr. John T. O’Connor, PE Tom O’Connor, PE

421 Sewage Disposal to 1950

Storm Drains: Flushings to Streams

Dilution: Waste Assimilative Capacity 1887-1900: (Chicago) Rudolf Hering Main Drainage Canal, Sanitary District

Broad Land Disposal 1876: Soil Clogging, Harmful to Crops

Intermittent (Biological Treatment) 1887: Lawrence (Mass.) Experiment Station

Treatment Septic Tanks, Tile Fields Residential Systems – 1910 Unsewered Households

Residential Waste Disposal: Estimate Waste Quantities and Strength

Engineering of the and Soil Absorption Systems Residential Flow Rates - 2000

Residences* gallons/person/day Low Income 50 Median 60 Luxury 80

Peak Flow Factors Month 2 Day 4 Hour 6

* Average: 3 residents per household Residential Water Use - 2000

Household Use gallons / day Laundry 25 Dishwashing 10 Miscellaneous 5

Personal (per capita) Use Bathing 20 Flushing 17 Cooking and Drinking 3 Sewage Characterization

Circa 1900: Nitrate, Ammonium Ion, Albuminoid N Chloride,

Suspended Solids; Settleable (Imhoff cone) Oxygen Consumed, BOD; Relative Stability Septic Odor, Hydrogen Sulfide; Cloudiness Bacteria (1899, APHA, First Standard Method) Analysis of Domestic Waste

Biochemical Oxygen Demand* 400 mg O / l Suspended Solids* 450 mg / l Organic Nitrogen 50 mg N / l + NH4 (oxygen demand) 15 mg N / l Grease (Scum) 70 mg / l

*Add 15% for in-sink garbage grinder Unsewered Systems

On-Site Treatment and Disposal: Flow Range: 0.2 to 2 m3/ day

Septic Tanks (Settling; Fermentation): • 1 to 2 day retention; 2 meters deep • scum, removal every 6 to 12 months • sludge to lagoons, earth-covered trenches • or plowed into land after partial drying on surface • soil absorption systems for tank overflow Septic Tank

Unit Capacity: 4 to 16 people 500 - 2000 gallons 90 -300 cubic feet 1-3 compartments L/W: 3/1; D: 4-6 ft. Scum, gas baffles Filter Vault Tile Fields Sub-Surface Disposal

Gravel-filled Trenches Open-Joint Tiles Infiltration to Vadose Zone

Biological Slime Formation Mineral Precipitates, FeS

Release of Gases, H2S, CH4

Soil Acceptance Rate: 0.3 to 0.5 gpd/sf Waste Treatment Methods

Intermittent (Sand) Filtration Rivers Pollution Commission (Great Britain) (1870) Mass. State Board of Health, Lawrence Experiment Station (effective; bacterial treatment; abandoned for scarcity of material)

Primary (Plain) Sedimentation

Imhoff Tanks (sedimentation plus digestion) (1906) (two-story tank providing sludge storage and digestion) Madison-Chatham, New Jersey (1911)

Racks, Screens (protect pumps, remove large solids) Grit Chambers Worcester, Massachusetts (1904) Early

Experimental Biological (Secondary)

Contact Beds (England, coarse media contact) (1893) Glencoe, Illinois (stones, gravel) (1901)

Trickling Filters (Reading, Pennsylvania) (1908) (revolving pipes and sprays over stone beds; biological treatment by attached growth)

Separate Sludge Digestion, sludge drying beds (1912) Birmingham, England; Baltimore, MD ( in covered, heated, stirred tanks)

Activated Sludge (suspended biological growth) Lawrence Experiment Station, Massachusetts (1912) (return of to influent) (1914) Sewage Disposal - 1930 U.S. Sewage Disposal (Cities > 100,000 Population)

“Dilution is the Solution to Pollution”

Treatment Population % None, Dilution alone 16,900,000 46.4 Fine Screening, Dilution 8,500,000 23.3 Sedimentation, Dilution 5,700,000 15.6 Trickling Filtration, Dilution 2,500,000 6.9 Activated Sludge, Dilution 2,600,000 7.1

14% of population of major cities had biological treatment. Microscreens

• 5 HP Drive Motor • 3 to 6” Head Loss • 75% Submergence • 15 to 60 µm Mesh Sizes • 15 to 150 fpm Drum Speed • 10’ Diameter for 3 to 10 mgd • 5% Backwash Flow @ 15 psi Karl Imhoff

1906: Taschenbuch der Stadtentwasserung Sewers:Open ditches with concrete slabs Two-Storied Settling and Digestion Tanks

1913-1934: 70 works constructed, Ruhr River

1929 : Karl Imhoff and Gordon Fair (Harvard) The Arithmetic of Sewage Treatment Works

Imhoff Tank patented in 1906; first operated in 1908 Imhoff Tank Treatment Plant Population: 1000 40,000 gpd

Manually-Cleaned Bar Rack Imhoff Tank Settling Compartments and Gas Vents

Gas Rising from Gas Vent Raw Sludge Drying Beds Sewage Effluent entering Stream

50% Suspended Solids Removal 50% Reduction in Oxygen Demand

Primary Treatment 4,500 / 0.5 mgd

Prechlorination Primary Chlorine Contact Chamber Heated Sludge Digester Sand Drying Beds Prechlorination and Sampling Dual, Manually-Cleaned Bar Screens Rectangular, Mechanically-Cleaned Clarifiers Scum Removal Chlorine Contact Chamber Effluent Sampling Imhoff Cones Heated Digester Floating Cover Sand Drying Beds Chemical Treatment

Lime + Ferric Chloride Sludge Treatment Lime Feeder Lime Feed Ferric Chloride FeCl3 + Lime Feed Chemical Treatment Basin Coagulated Sewage Physical Treatment Solids Removal Biological Waste Treatment

England: 1893: - Attached Growth 1914: Activated Sludge - Suspended Growth

United States: 1901: Trickling Filter - Madison, Wisconsin 1909: Imhoff Tank - settling and digestion 1914: Chlorination - effluent disinfection 1916: Activated Sludge - San Marcos, TX Trickling Filter

Popular with Birds - “BOD flies away” Activated Sludge Plant

Activated Sludge Process

Activated Sludge (bacterial cell mass) is recovered from the Secondary and returned to the influent of the Aeration Tank. Aeration Tanks Return Sludge Mixed Liquor Acivated Sludge Plant Performance Evaluation

Imhoff Cone Air Compressor + Gas Engine Covered Drying Beds Community Water Supply - Wilder, TN. - 1942 A hand-pumped well ... No paved streets ... No need for sewage treatment here ...

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